What is the li_fat_id cookie?
li_fat_id ("first-party ad tracking id") is an HTTP cookie set by LinkedIn when a page contains the LinkedIn Insight Tag or a LinkedIn social plugin, such as a "Share" or "Follow" button. It is issued as a first-party cookie directly from the visited site's domain, not from linkedin.com.
It usually appears as soon as a visitor accepts marketing cookies and the LinkedIn script executes, later used by LinkedIn to connect on-site visits with the user's LinkedIn account or active ad campaigns.
What data it stores
The cookie stores a unique identifier generated by LinkedIn, used to recognize the visitor's browser on later visits. LinkedIn does not publicly document the exact value format, and it may vary; it should not be treated as a stable, publicly specified value.
Data collected through li_fat_id is sent to LinkedIn's servers (domains such as linkedin.com or ads.linkedin.com) and used within the LinkedIn Ads ecosystem for reporting and campaign optimization.
What it is used for
The main purpose is conversion attribution: LinkedIn uses li_fat_id to determine whether a user who saw or clicked a LinkedIn ad later took an action on the site, such as submitting a form, making a purchase, or signing up.
For site owners running LinkedIn Ads campaigns, this cookie underpins conversion reporting and enables retargeting and custom audience features in LinkedIn Campaign Manager.
Does it require consent?
li_fat_id is classified as a marketing (advertising/tracking) cookie and is not strictly necessary for the site to function. Under GDPR and the ePrivacy Directive (transposed in Romania via Law 506/2004), this type of cookie requires the visitor's explicit, prior consent before being set.
- The site owner must disclose the cookie in the cookie policy, including provider, category, and duration.
- The LinkedIn Insight Tag script should only load after consent for the marketing category has been given.
- Rejecting consent must be as easy as accepting it.
How to block or delete li_fat_id
Visitors can delete or block this cookie via browser settings (per-site cookie management) or use anti-tracking features such as Safari's "Prevent Cross-Site Tracking" or dedicated browser extensions. Removing it does not break site functionality, only the accuracy of LinkedIn's ad reporting.
For site owners, the cookie must be technically blocked until consent is obtained. A CMP such as CookieFix can automatically prevent the LinkedIn Insight Tag from loading (and li_fat_id from being set) until the visitor explicitly accepts the marketing category.
Frequently asked questions
It doesn't store sensitive personal data directly, but it is used for ad tracking and behavioral profiling, which is why it's legally classified as a marketing cookie requiring consent.
It's most likely triggered by the LinkedIn Insight Tag or a LinkedIn social plugin (share/follow button) installed on the site, which sets the cookie regardless of active ad campaigns.
Its typical duration is around 30 days from the last interaction, after which it expires automatically, though it can be renewed on a new visit if consent is maintained.
Yes, as a third-party marketing cookie set by LinkedIn, it must be listed with its name, provider, purpose, and duration in the site's cookie policy, per GDPR/ePrivacy requirements.